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Android使用觀察者模式Observer實(shí)現(xiàn)網(wǎng)絡(luò)狀態(tài)監(jiān)聽

 更新時間：2018年05月29日 09:31:05   作者：Hui_2017  
這篇文章主要為大家詳細(xì)介紹了Android使用觀察者模式Observer實(shí)現(xiàn)網(wǎng)絡(luò)狀態(tài)監(jiān)聽，具有一定的參考價值，感興趣的小伙伴們可以參考一下

在Android開發(fā)過程中，很多時候都會用到當(dāng)前網(wǎng)絡(luò)的狀態(tài)判斷以及網(wǎng)絡(luò)狀況發(fā)生變化的時候做出相應(yīng)的反應(yīng)，要想監(jiān)聽網(wǎng)絡(luò)狀態(tài)，用觀察者模式再合適不過了，廢話不多說，直接上代碼。

觀察者模式屬于面向?qū)ο蟮?3中設(shè)計(jì)模式之一，不了解的同學(xué)請自行Google

既然用觀察者模式，自然離不開觀察者模式里最重要的兩個類Subject和Ovserver了

Subjcet接口：

/**
 * Description: observer subject
 * author: Wang
 * date: 11/28/16 11:19 AM
 * 
 * Copyright©2016 by wang. All rights reserved.
 */
public interface NetConnectionSubject {

  /**
   * 注冊觀察者
   *
   * @param observer
   */
  public void addNetObserver(NetConnectionObserver observer);

  /**
   * 移除觀察者
   *
   * @param observer
   */
  public void removeNetObserver(NetConnectionObserver observer);

  /**
   * 狀態(tài)更新通知
   *
   * @param type
   */
  public void notifyNetObserver(int type);
}

Observer接口：

/**
 * Description: observer
 * author: Wang
 * date: 11/28/16 11:20 AM
 * 
 * Copyright©2016 by wang. All rights reserved.
 */
public interface NetConnectionObserver {

  /**
   * 通知觀察者更改狀態(tài)
   *
   * @param type
   */
  public void updateNetStatus(int type);
}

在Android里，最適合實(shí)現(xiàn)Subject類的，莫過于Application了，因?yàn)樗治ㄒ欢疑芷诰褪沁@個App的生命周期：

/**
 * Description: App's application should extend this class
 * author: Wang
 * date: 11/28/16 10:34 AM
 * 
 * Copyright©2016 by wang. All rights reserved.
 */
public abstract class BaseApplication extends Application implements NetConnectionSubject {

  protected static BaseApplication instance;

  private int currentNetType = -1;

  private List<NetConnectionObserver> observers = new ArrayList<>();


  public static BaseApplication getInstance() {
    return instance;
  }

  /**
   * current net connection type
   *
   * @return
   */
  public int getCurrentNetType() {
    return currentNetType;
  }

  /**
   * current net connection status
   *
   * @return
   */
  public boolean isNetConnection() {
    return currentNetType == NetWorkUtil.NET_NO_CONNECTION ? false : true;
  }

  @Override
  public void onCreate() {
    super.onCreate();

    instance = this;

    currentNetType = NetWorkUtil.getConnectionType(this);

  }

  @Override
  public void addNetObserver(NetConnectionObserver observer) {
    if (!observers.contains(observer)) {
      observers.add(observer);
    }
  }

  @Override
  public void removeNetObserver(NetConnectionObserver observer) {
    if (observers != null && observers.contains(observer)) {
      observers.remove(observer);
    }
  }

  @Override
  public void notifyNetObserver(int type) {

    /**
     * 避免多次發(fā)送相同的網(wǎng)絡(luò)狀態(tài)
     */
    if (currentNetType == type) {
      return;
    } else {
      currentNetType = type;
      if (observers != null && observers.size() > 0) {
        for (NetConnectionObserver observer : observers) {
          observer.updateNetStatus(type);
        }
      }
    }
  }
}

具體誰要實(shí)現(xiàn)Observer接口，就要看具體場景了，這里以Activity為栗子吧：

/**
 * Description: TODO
 * author: WangKunHui
 * date: 16/12/30 下午3:08
 * <p>
 * Copyright©2016 by wang. All rights reserved.
 */
public class TestActivity extends Activity implements NetConnectionObserver {

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    /**省略一些方法**/
    BaseApplication.getInstance().addNetObserver(this);
  }

  @Override
  public void updateNetStatus(int type) {
    //當(dāng)監(jiān)聽網(wǎng)絡(luò)狀態(tài)發(fā)生變化 這里會及時的收到回饋
  }

  @Override
  protected void onDestroy() {
    super.onDestroy();

    BaseApplication.getInstance().removeNetObserver(this);
  }
}

這里有個地方一定要注意：當(dāng)Activity銷毀的時候，一定要把這個觀察者從觀察者隊(duì)列里移除掉！否者會發(fā)生內(nèi)存泄漏

到這里，觀察者模式已經(jīng)寫完了，謝謝收看。

讀者：你是不是忘了點(diǎn)什么，說好的網(wǎng)絡(luò)監(jiān)聽呢？
我：Easy easy~  剛剛只不過是中場休息

如果只有上面那么多的話，是不能監(jiān)聽網(wǎng)絡(luò)狀態(tài)的，想要監(jiān)聽網(wǎng)絡(luò)狀態(tài)的變化，還得靠我們的廣播接收者啊，有請：

/**
 * Description: 網(wǎng)絡(luò)連接狀態(tài)的監(jiān)聽
 * author: Wang
 * date: 16/8/3 下午10:54
 * 
 * Copyright©2016 by wang. All rights reserved.
 */
public class NetConnectionReceiver extends BroadcastReceiver {

  @Override
  public void onReceive(Context context, Intent intent) {

    if (intent.getAction().equals(ConnectivityManager.CONNECTIVITY_ACTION)) {
      int connectionType = NetWorkUtil.getConnectionType(context);

      /**
       * 更改網(wǎng)絡(luò)狀態(tài)
       */
      if (BaseApplication.getInstance() != null) {
        BaseApplication.getInstance().notifyNetObserver(connectionType);
      }
    }
  }
}

NetWorkUtil:

/**
 * @author Wang
 * @version 1.0.0
 * @description 網(wǎng)絡(luò)操作工具類
 * @create 2014-2-18 上午09:22:30
 * @company 
 */

public class NetWorkUtil {

/**
   * 無網(wǎng)絡(luò)鏈接
   */
  public static final int NET_NO_CONNECTION = 0;

  /**
   * wifi
   */
  public static final int NET_TYPE_WIFI = 1;

  public static final int NET_TYPE_2G = 2;

  public static final int NET_TYPE_3G = 3;

  public static final int NET_TYPE_4G = 4;

  /**
   * 未知的網(wǎng)絡(luò)類型
   */
  public static final int NET_TYPE_UNKNOWN = 5;

 /**
   * 獲取網(wǎng)絡(luò)類型
   *
   * @param context
   * @return
   */
  public static int getConnectionType(Context context) {

    int netType = NET_NO_CONNECTION;

    NetworkInfo networkInfo = ((ConnectivityManager) 
   context.getSystemService(Context.CONNECTIVITY_SERVICE)).getActiveNetworkInfo();

    if (networkInfo == null) {

      netType = NET_NO_CONNECTION;
    } else {

      if (networkInfo.getType() == ConnectivityManager.TYPE_WIFI) {
        netType = NET_TYPE_WIFI;
      } else {

        int networkType = networkInfo.getSubtype();

        switch (networkType) {
          case TelephonyManager.NETWORK_TYPE_GPRS:
          case TelephonyManager.NETWORK_TYPE_EDGE:
          case TelephonyManager.NETWORK_TYPE_CDMA:
          case TelephonyManager.NETWORK_TYPE_1xRTT:
          case TelephonyManager.NETWORK_TYPE_IDEN: //api<8 : replace by 11
            netType = NET_TYPE_2G;
            break;
          case TelephonyManager.NETWORK_TYPE_UMTS:
          case TelephonyManager.NETWORK_TYPE_EVDO_0:
          case TelephonyManager.NETWORK_TYPE_EVDO_A:
          case TelephonyManager.NETWORK_TYPE_HSDPA:
          case TelephonyManager.NETWORK_TYPE_HSUPA:
          case TelephonyManager.NETWORK_TYPE_HSPA:
          case TelephonyManager.NETWORK_TYPE_EVDO_B: //api<9:replace by 14
          case TelephonyManager.NETWORK_TYPE_EHRPD: //api<11:replace by 12
          case TelephonyManager.NETWORK_TYPE_HSPAP: //api<13:replace by 15
            netType = NET_TYPE_3G;
            break;
          case TelephonyManager.NETWORK_TYPE_LTE:  //api<11:replace by 13
            netType = NET_TYPE_4G;
            break;
          default:

            String subType = networkInfo.getSubtypeName();

            if (subType.equalsIgnoreCase("TD-SCDMA") || 
              subType.equalsIgnoreCase("WCDMA") ||
              subType.equalsIgnoreCase("CDMA2000")) {
              netType = NET_TYPE_3G;
            } else {
              netType = NET_TYPE_UNKNOWN;
            }

            break;
        }
      }
    }
    return netType;
  }
}

好了，到這里，標(biāo)題上所有的內(nèi)容已經(jīng)寫完了，最后，別忘了權(quán)限和注冊廣播接收者。

以上就是本文的全部內(nèi)容，希望對大家的學(xué)習(xí)有所幫助，也希望大家多多支持腳本之家。

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